Generally, a clamp is used for connecting piping members, each of which has a flange portion disposed at an end thereof. The clamp is provided with a groove portion which extends in a circumference direction thereof, for example, referring to JP-8-219351A. The flange portions are held in the groove portion to be clamped, so that the piping members are axially fixed to each other.
For example, referring to FIG. 9, a clamp 101 made of a resin includes a circular holding portion 110 for accommodating the flange portions of the piping members, and a flexion-shaped hinge portion 120 which protrudes from the holding portion 110 toward a diametrically outer side thereof.
The hinge portion 120 can be resiliently deformed when the clamp 101 is opened/closed. In this case, the inner diameter of the holding portion 110 is changeable responding to a deformation of the flexion-shaped hinge portion 120, to accommodate the variation of the outer diameters of the flange portions.
However, in the case where the variation of the outer diameters of the flange portions is large, the flexion-shaped hinge portion 120 is to be large-sized to accommodate the variation. Thus, the protrusion amount ‘C’ of the hinge portion 120 with respect to an outer surface of the holding portion 110 becomes large, so that the space occupied by the clamp 101 at the joint part of the piping members is enlarged.